Thermal interface for plurality of discrete electronic devices

Abstract

A thermal interface for discrete semiconductor devices (such as IGBT's) having a thermally conductive structure, a PCB populated with discrete electronic components, and each of the discrete semiconductor devices having a housing extending beyond the edge of the PCB and in a direction substantially parallel to a plane of the PCB, and a clamp bar secured to the thermally conductive structure adapted to compressively secure each housing to the thermally conductive structure and adapted to maintain thermal contact between a surface of each housing and the surface of the thermally conductive structure. A thermally conductive and electrically insulative pad is positioned between the semiconductor device housing and the thermally conductive structure. A casing enclosing the interface and PCB includes the thermally conductive structure formed on a backwall of the casing.

What is claimed is: 
     
       1. A thermal interface for a plurality of discrete electronic semiconductor devices, the interface comprising:
 a thermally conductive structure extending from a base; 
 a PCB mounted in a position relative to the thermal conductive structure and populated with discrete electronic components; 
 each of the plurality of discrete electronic semiconductor devices having a housing and terminal pins extending from the housing, and each housing extending in a direction substantially parallel to a plane comprising the PCB beyond an edge of the PCB; and 
 a U-shaped clamp bar secured to the thermally conductive structure via a plurality of projections being integrally formed from the thermally conductive structure, and extending upward from a housing supporting surface of the thermally conductive structure and spaced apart from one another along a length of the clamp bar, 
 each of the plurality of integrally formed projections having an insulative ferrule completely surrounding the projection and providing a fastening surface facing the clamp bar against which the clamp bar is securably fastened so as to securably fasten the clamp bar to the thermally conductive structure with each housing positioned between the clamp bar and the housing supporting surface of the thermally conductive structure, 
 wherein the clamp bar is adapted to compressively secure each housing between the clamp bar and the housing supporting surface of the thermally conductive structure and to maintain thermal contact between a surface of each housing and the housing supporting surface of the thermally conductive structure. 
 
     
     
       2. The interface of  claim 1 , further comprising a thermally conductive and electrically insulative pad positioned upon the surface of the thermally conductive structure between the surface of each housing and the thermally conductive structure. 
     
     
       3. The interface of  claim 1 , wherein the clamp bar comprises a plurality of spring clamp elements, each spring clamp element compressively securing a respective one of the plurality of devices to maintain thermal contact between a surface of the device housing and the thermally conductive structure. 
     
     
       4. The interface of  claim 3 , wherein the plurality of spring clamp elements are formed on a base wall of the clamp bar. 
     
     
       5. The interface of  claim 4 , wherein the U-shaped clamp bar comprises the base wall being bounded along opposite side edges by side walls. 
     
     
       6. The interface of  claim 1 , wherein each of the plurality of discrete electronic semiconductor devices comprises a switching circuit. 
     
     
       7. The interface of  claim 6 , wherein each of the plurality of discrete electronic semiconductor devices comprises an insulated-gate bipolar transistor (IGBT). 
     
     
       8. The interface of  claim 1 , wherein the thermally conductive structure is integrally formed with the base, the PCB being mounted to the base. 
     
     
       9. The interface of  claim 1 , wherein the clamp bar includes a plurality of spring clamp elements, each spring clamp element compressively securing a respective one of the plurality of devices to maintain thermal contact between a surface of the device housing and a thermally conductive and electrically insulative pad positioned upon the surface of the thermally conductive structure. 
     
     
       10. The interface of  claim 1 , wherein the thermally conductive structure extends from the base in a direction substantially perpendicular to the plane of the PCB and substantially perpendicular to the surface of each housing, the surface of each housing being substantially parallel with one another, such that the thermally conductive structure extends from the base to accommodate a required distance between the base and a lower surface of the PCB, the lower surface of the PCB having the discrete electronic components attached thereon. 
     
     
       11. A motor vehicle power electronics system having a thermal interface for a plurality of discrete electronic semiconductor devices, the system comprising:
 a casing adapted to enclose the plurality of devices in an enclosed space, the casing having a thermally conductive structure extending inward into the enclosed space from a wall of the casing; 
 a PCB mounted within the enclosed space and populated with discrete electronic components; 
 each of the plurality of discrete electronic semiconductor devices having a housing and terminal pins extending from the housing, and each housing extending in a direction substantially parallel to a plane comprising the PCB beyond an edge of the PCB; and 
 a U-shaped clamp bar secured to the thermally conductive structure via a plurality of projections being integrally formed from the thermally conductive structure, and extending upward from a housing supporting surface of the thermally conductive structure and spaced apart from one another along a length of the clamp bar, 
 each of the plurality of integrally formed projections having an insulative ferrule completely surrounding the projection and providing a fastening surface facing the clamp bar against which the clamp bar is securably fastened so as to securably fasten the clamp bar to the thermally conductive structure with each housing positioned between the clamp bar and the housing supporting surface of the thermally conductive structure, 
 wherein the clamp bar is adapted to compressively secure each housing between the clamp bar and the housing supporting surface of the thermally conductive structure and to maintain thermal contact between a surface of each housing and the housing supporting surface of the thermally conductive structure. 
 
     
     
       12. The system of  claim 11 , further comprising a thermally conductive and electrically insulative pad positioned upon the surface of the thermally conductive structure between the surface of each housing and the thermally conductive structure. 
     
     
       13. The system of  claim 11 , wherein the clamp bar comprises a plurality of spring clamp elements, each spring clamp element compressively securing a respective one of the plurality of devices to maintain thermal contact between a surface of the device housing and the thermally conductive structure. 
     
     
       14. The system of  claim 13 , wherein the plurality of spring clamp elements are formed on a base wall of the clamp bar. 
     
     
       15. The system of  claim 14 , wherein the U-shaped clamp bar comprises the base wall being bounded along opposite side edges by side walls. 
     
     
       16. The system of  claim 11 , wherein each of the plurality of discrete electronic semiconductor devices comprises a switching circuit. 
     
     
       17. The system of  claim 16 , wherein each of the plurality of discrete electronic semiconductor devices comprises an insulated-gate bipolar transistor (IGBT). 
     
     
       18. The system of  claim 11 , wherein the thermally conductive structure is integrally formed with the casing, the PCB being mounted to the casing. 
     
     
       19. The system of  claim 11 , wherein the clamp bar includes a plurality of spring clamp elements, each spring clamp element compressively securing a respective one of the plurality of devices to maintain thermal contact between a surface of the device housing and a thermally conductive and electrically insulative pad positioned upon the surface of the thermally conductive structure. 
     
     
       20. The system of  claim 11 , wherein the thermally conductive structure extends from the casing wall inward into the enclosed space in a direction substantially perpendicular to the plane of the PCB and substantially perpendicular to the surface of each housing, the surface of each housing being substantially parallel with one another, such that the thermally conductive structure extends inward from the casing wall to accommodate a required distance between the casing wall and a lower surface of the PCB, the lower surface of the PCB having the discrete electronic components attached thereon.